1. Technical Field
The present invention relates to an airbag apparatus that expands from an inside of a case toward a cabin upon collision and the like and thus relieves and absorbs shock to protect a passenger.
2. Related Art
As an apparatus that relieves and absorbs shock, which results from collision and the like, to protect a passenger, an airbag apparatus has been known. For example, an airbag apparatus for a steering that expands toward a cabin upon collision and then deploys between a steering and a driver is installed in a central part of the steering of a vehicle.
In the airbag apparatus for a steering, an airbag is accommodated in a pad positioned at a center of the steering, with being folded toward an inflator that ejects gas for inflation. The pad that functions as a case for accommodating the airbag is provided with a recess-shaped tear line that is thinner than the other part so that it is fractured by pressure applied when the airbag is inflated and deployed. Thereby, when the airbag expands, the pad is fractured along the tear line, so that the airbag is inflated and expanded toward the cabin from an opening resulting from the fracture.
In most cases, an emblem is attached on the central part of the steering. Accordingly, in the airbag apparatus for a steering, it is necessary to provide the tear line while avoiding the emblem. For example, in an airbag apparatus disclosed in JP 2002-137709A, as shown in FIG. 13, a tear line 1b that extends in a lateral direction so as to connect two tear lines 1a extending in a longitudinal direction is provided to divide a pad 1 into an upper door A and a lower door B. However, the tear line 1b is provided to upwardly bypass an emblem 4.
FIG. 14 is a sectional view of showing a state that the airbag starts to inflate from an inside of the pad toward a cabin. In FIG. 14, a left side is the cabin-side.
An airbag 2 accommodated in the pad 1 is about to inflate by gas ejected from an inflator 3, from a part to which the inflator 3 is attached. However, when the tear line 1b is provided at a position that is deviated upwards from a center of the pad 1, as the airbag apparatus disclosed in JP 2002-137709A, an opening that is formed when the pad 1 is fractured is located at a position that is deviated upwards from the attachment position of the inflator 3, as shown in FIG. 14. Therefore, the airbag 2 is apt to deploy upwards, as shown with an outline arrow in FIG. 14, so that it is difficult to deploy the airbag 2 toward the front of the steering in a balanced manner.
The above problem is commonly caused when the position of the tear line provided to the case accommodating the airbag and the inflator is deviated from the center of the inflator, which is a base point of the inflation and deployment of the airbag. In addition, the above problem may be caused not only in the airbag apparatus for a steering but also an airbag apparatus for an assistant passenger's seat provided to a dashboard.